Buggy code:
public final class GuiPackage implements LocaleChangeListener { private static final Logger log = LoggingManager . getLoggerForClass ( ) ; private static GuiPackage guiPack ; private boolean dirty = false ; private Map nodesToGui = new HashMap ( ) ; private Map guis = new HashMap ( ) ; private Map testBeanGUIs = new HashMap ( ) ; private JMeterTreeNode currentNode = null ; private boolean currentNodeUpdated = false ; private JMeterTreeModel treeModel ; private JMeterTreeListener treeListener ; private MainFrame mainFrame ; private GuiPackage ( ) { } public static GuiPackage getInstance ( ) { } public static GuiPackage getInstance ( JMeterTreeListener listener , JMeterTreeModel treeModel ) { } public JMeterGUIComponent getGui ( TestElement node ) { } public JMeterGUIComponent getGui ( TestElement node , Class guiClass , Class testClass ) { } public void removeNode ( TestElement node ) { } public JMeterGUIComponent getCurrentGui ( ) { } public JMeterTreeNode getNodeOf ( TestElement userObject ) { } public TestElement createTestElement ( Class guiClass , Class testClass ) { } public TestElement createTestElement ( String objClass ) { } private JMeterGUIComponent getGuiFromCache ( Class guiClass , Class testClass ) throws IllegalAccessException , InstantiationException { } public void updateCurrentGui ( ) { } public void updateCurrentNode ( ) { } public JMeterTreeNode getCurrentNode ( ) { } public TestElement getCurrentElement ( ) { } public void setDirty ( boolean dirty ) { } public boolean isDirty ( ) { } public HashTree addSubTree ( HashTree subTree ) throws IllegalUserActionException { } public HashTree getCurrentSubTree ( ) { } public JMeterTreeModel getTreeModel ( ) { } public void setTreeModel ( JMeterTreeModel newTreeModel ) { } public ValueReplacer getReplacer ( ) { } public void setMainFrame ( MainFrame newMainFrame ) { } public MainFrame getMainFrame ( ) { } public void setTreeListener ( JMeterTreeListener newTreeListener ) { } public JMeterTreeListener getTreeListener ( ) { } public void displayPopUp ( MouseEvent e , JPopupMenu popup ) { } public void displayPopUp ( Component invoker , MouseEvent e , JPopupMenu popup ) { } public void localeChanged ( LocaleChangeEvent event ) { } private String testPlanFile ; public void setTestPlanFile ( String f ) { testPlanFile = f ; <START_BUG> getMainFrame ( ) . setTitle ( JMeterUtils . getExtendedFrameTitle ( testPlanFile ) ) ; <END_BUG> getMainFrame ( ) . setFileRevertEnabled ( ( f != null ) ) ; getMainFrame ( ) . setProjectFileLoaded ( f ) ; try { FileServer . getFileServer ( ) . setBasedir ( testPlanFile ) ; } catch ( IOException e1 ) { GuiPackage . log . error ( "Failure<seq2seq4repair_space>setting<seq2seq4repair_space>file<seq2seq4repair_space>server's<seq2seq4repair_space>base<seq2seq4repair_space>dir" , e1 ) ; } } public String getTestPlanFile ( ) { } public static void showErrorMessage ( final String message , final String title ) { } public static void showInfoMessage ( final String message , final String title ) { } public static void showWarningMessage ( final String message , final String title ) { } public static void showMessage ( final String message , final String title , final int type ) { } }

Fix:
getMainFrame ( ) . setExtendedFrameTitle ( testPlanFile ) ;